Redefining High Emergency Department Utilization for Sickle Cell Disease

Sickle cell disease (SCD) is a complex hemoglobinopathy. Vaso-occlusive episodes are the primary cause of emergency department (ED) utilization among individuals with SCD. Literature lacks a standardized definition for high ED utilization.

To explore ED utilization, redefine high ED utilization, and describe factors associated with super-high ED utilization among individuals with SCD.

This retrospective cohort study analyzed the North Carolina Hospital Discharge Datasets (2013-2019). Participants were included if they had SCD, defined as at least 3 SCD visits (ED, inpatient, or outpatient surgery) in a rolling 5-year period. All age groups, sexes, and payers, regardless of state of residence, were included. Data were analyzed from July 2023 to August 2024.

Variables included sex, race, ethnicity, age, age at death, distance (in miles) to the closest SCD center, number of annual ED visits, and social vulnerability index (SVI).

To determine ED utilization categories, first the distribution of people based on the number of annual ED visits was examined, then the categories across years were identified to determine the data-informed cutoff for each category. Univariate analysis determined differences between participants based on the ED utilization category using χ2 tests of independence or analysis of variance, as applicable. Descriptive statistics were conducted to describe characteristics of utilization in the sample and by ED utilization group. A parsimonious multinomial regression was conducted using significant factors from the univariate analysis.

The cohort included 9964 unique patients (5364 [53.83%] female; mean [SD] age, 24.49 [17.54] years), including 9355 Black patients (93.89%), with 100 188 total ED visits from 2013 to 2019. ED visits were categorized into 4 levels: low (0-1 visits per year), moderate (2-9 visits per year), high (10-32 visits per year), and super high (≥33 visits per year). A small subset (178 patients [1.79%]) exhibited super-high ED utilization, contributing disproportionately to the total number of ED visits. Older age, younger age for in-facility deaths, and higher SVI were significantly associated with higher ED utilization. Patients with high utilization were more likely to die, die younger (eg, median [IQR] age at death, 33.0 [30.0-44.0] years in the super-high utilization group vs 50 [38.0-61.0] years in the moderate utilization group), use multiple EDs (eg, 93.8% of participants in the super-high utilization group vs 40.08% of participants in the moderate utilization group), and reside in counties more disadvantaged on socioeconomic and transportation characteristics.

This cohort study of 7 years of North Carolina Hospital Discharge Data described 4 new categories of ED utilization in SCD. These categories could be used to reframe how high ED use is determined.